Disclaimer : this is an AU where Bowser Jr and Toadette are older I do not ship them in canon
It took me almost 8 years to figure out how to write this arc but I'm glad I firgured it out (you can read it on my fanfiction.net account btw :0 ) but yes this part of the AU where Bubbles is born (The Mushroom Kingdom being attacked at this time by Bowser, explaning the darkish tone) since Bowser Jr is dumb and completely unaware that koopa's come out of eggs as babies, he is heavily confused as to why she's a baby and not a full grown adult (and to clarify Toadette did NOT birth that egg, Junior had gotten it somewhere in the Darklands) sooo now he's a father congrats sir.

All drawn in Photoshop CC